Heat pump cycle system and method of providing combined cooling and heating supply

ABSTRACT

A heat pump cycle system and a method for providing combined cooling and heating supply are disclosed. The heat pump cycle system comprises a working medium reservoir, an absorbing solution reservoir, and a compression heat pump. The upper portions of the working medium reservoir and the absorbing solution reservoir are connected by a gas passage. The compression heat pump comprises a compressor, a condenser, a throttle valve and an evaporator, all of which are connected by a steam pipeline accordingly. The working medium reservoir contains a working medium and further comprises a first heat exchanger, and the evaporator. The absorbing solution reservoir contains an absorbing solution and further comprises a second heat exchanger and the condenser. The system utilizes electricity during the electricity consumption trough, to operate the compression heat pump cycle during the reproducing process.

CROSS REFERENCE TO RELATED APPLICATION

This application is a National Phase Application of International Patent Application No. PCT/CN2009/001276, filed on Nov. 17, 2009. This application claims priority to and the benefit of the above PCT application and of Chinese Patent Application Serial No. 200810226806.7, filed on Nov. 17, 2008, the disclosure of each of which is incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a technology of cooling and heating supply in the thermal engineering field, and particularly relates to a heat pump cycle system that combines an absorptive heat pump and a compression heat pump together, and also a method of providing a combined cooling and heating supply.

BACKGROUND OF THE INVENTION

The current absorptive heat pump cycle systems utilizing an absorbing solution can condense steam of components with low boiling points under certain conditions, and can intensively absorb steam of the components with low boiling points under other conditions. The absorptive heat cycle mostly uses the absorbing solution with two components. Often the component with a low boiling point is referred as the working medium, and the component with a high boiling point is referred as the absorbent. And the two components together form a working medium pair. A common working medium pair is water-lithium bromide with water as the working medium and lithium bromide as the absorbent. The most current absorptive heat pump cycle system mainly comprises a generator internally equipped with a heat exchanger, a condenser internally equipped with a heat exchanger, an evaporator internally equipped with a heat exchanger, and an absorber internally equipped with a heat exchanger. Some current absorptive heat pump cycle system further comprises auxiliary devices such as an absorbing solution self-heating exchanger, an absorbing solution pump, a throttle valve, and etc. The generator and condenser are usually connected through steam pipelines, and the evaporator and the absorber are usually also connected through steam pipelines. The absorbing solution circulates between the generator and the absorber through absorbing solution pipelines.

A working process of the most current absorptive heat pump circulation includes (1) utilizing a heat source (such as steam, hot water, combustion gas, and etc.) to heat a lithium bromide solution with a specific concentration transferred from the absorber in the generator, causing water to evaporate from the lithium bromide solution forming a water steam and a second lithium bromide solution with a greater concentration that circulating into the absorber; (2) the water steam entering into the condenser through a steam pipeline, and being condensed into water by a condensing working medium in the heat exchanger; (3) the water entering into an evaporator through a water pipeline, absorbing the heat of a working medium in a heat exchanger forming a low pressure water steam, and the temperature of the working medium in the heat exchanger of the evaporator dropping after its heat being absorbed, thus forming a cooling output of the absorptive heat pump system; (4) the water steam entering into the generator through the steam pipeline, and being absorbed by the concentrated lithium bromide solution from the generator, and thus generating absorption heat, and as the concentration of the lithium bromide solution being reduced, the absorption heat being taken away by the condensing working medium in the heat exchanger of the absorber forming a heating output, and the second lithium bromide solution with the greater concentration circulating into the generator.

SUMMARY

The present invention provides a heat pump cycle system and a method of providing a combined cooling and heating supply. The present invention also discloses a heat pump cycle system with a simple structure, improved efficiency, and a lower manufacturing cost.

According to one embodiment of the present invention, a heat pump cycle system comprises a working medium reservoir, an absorbing solution reservoir and a compression heat pump. The compression heat pump is further comprises a compressor, a condenser, a throttle valve, and an evaporator, all of which are connected in order through pipelines. The working medium reservoir is connected with the upper portion of the absorbing solution reservoir through a steam passage. The working medium reservoir is filled with a working medium. The working medium reservoir further comprises a first heat exchanger. The evaporator is also set inside the working medium reservoir. The absorbing solution reservoir is filled with an absorbing solution. The absorbing solution reservoir further comprises a second heat exchanger. The condenser is also set inside the absorbing solution reservoir.

According to one embodiment of the present invention, the heat pump cycle system can further comprise an absorbing solution recycle pump, an absorbing solution spray system, a working medium recycle pump, and a working medium spray system. The absorbing solution recycle pump is configured to situate between the absorbing solution reservoir and the absorbing solution spray system. The absorbing solution recycle pump recycles the absorbing solution between the absorbing solution reservoir and the absorbing solution spray. The working medium recycle pump is configured to situate between the working medium reservoir and the working medium spray system. The working medium recycle pump recycles the working medium between the working medium reservoir and the working medium spray system. The evaporator of the compression heat pump is configured to situate inside the working medium reservoir, or in the working medium circulation loop, or in the circulation loop of the first heat exchanger. The condenser of the compression heat pump is set inside the absorbing solution reservoir, or in the absorbing solution circulation loop, or in the circulation loop of the second heat exchanger.

According to one embodiment of the present invention, the absorption solution comprises a working medium and an absorbent. The working medium is selected from water, ammonia, methanol, ethanol, and mixtures thereof. The absorbent is selected from LiBr, NaBr, KBr, NH₄Br, MgBr₂, CaBr₂, LiI, NaI, KI, NH₄I, MgI₂, CaI₂, LiCl, NaCl, KCl, NH₄Cl, MgCl₂, CaCl₂, LiNO₃, NaNO₃, KNO₃, NH₄NO₃, Mg(NO₃)₂, Ca(NO₃)₂, and mixtures thereof.

According to one embodiment of the present invention, the absorbing solution is a saturated solution or a supersaturated solution.

According to one embodiment of the present invention, the heat pump cycle system further comprises at least one of a solar thermal collector, a terrestrial heat device, a reclaimed-water supply device and an air heat exchanger, for supplying heat to the first heat exchanger in the working medium reservoir.

According to one embodiment of present invention, a method of providing combined cooling and heating supply comprises a working process and a reproducing process. The working process and the reproducing process are carried out alternatively. During the working process, under a first pressure, a cooling medium circulates in a first heat exchanger, a heating medium circulates in a second heat exchanger, and a working medium in the working medium storage pump absorbs the heat of the cooling medium and evaporates into a gaseous working medium. The gaseous working medium enters an absorbing solution reservoir, and is absorbed by an absorbing solution with absorption heat being released. The cooling medium supplies cooling and the heating medium supplies heating. During the reproducing process, under a second pressure, a compression heat pump starts, the evaporator absorbs heat, the condenser releases heat with which the absorbing solution is heated and the working medium steam evaporates into the gaseous working medium from the absorbing solution. The gaseous working medium enters the working medium reservoir, and condenses into liquid.

According to one embodiment of the present invention, the second pressure is lower than the first pressure.

According to one embodiment of present invention, the heat pump cycle system utilizes low ebb electricity during the reproducing process.

According to one embodiment of present invention, the first pressure is higher than 1 kPa, and the second pressure is between 0.6 kPa and 1 kPa.

According to one embodiment of present invention, the cooling medium in the first heat exchanger is one or a mixture of two or more of a solar thermal collector, a terrestrial heat device, a reclaimed-water supply device, and an air heat exchanger.

The present invention can also relate to a heat pump cycle system and a method of providing combined cooling and heating by integrating an absorptive heat pump circulation with a compression heat pump circulation. According to one embodiment of the present invention, the heat pump cycle system comprises a working medium reservoir containing a working medium, and is coupled with a first heat exchanger and an evaporator, an absorbing solution reservoir containing an absorbing solution and is coupled with a second heat exchanger and a condenser. The working medium reservoir is connected to the absorbing solution reservoir through a steam passage forming a circulation loop of an absorptive heat pump. The circulation loop of the absorptive heat pump is used, during the working process, to provide cooling output through the first heat exchanger, and simultaneously provide heating output through the second heat exchanger. This is accomplished as the working medium evaporating and absorbing heat from the working medium reservoir, and condensing and releasing heat into the absorbing solution reservoir. According to one embodiment of the present invention, the heat pump cycle system further comprises a compressor and a valve, for example a throttle valve. The compressor, the condenser, the throttle valve and the evaporator forms a circulation loop of the compressive heat pump. The compressive heat pump is used, during the reproducing process, to absorb heat by evaporating a refrigerant to form a gaseous working medium in the evaporator of the working medium reservoir, and releasing heat and condensing in the condenser of the absorbing solution reservoir upon being compressed, and thus heating the absorbing solution in the absorbing solution reservoir. The reproducing process is accomplished as the gaseous working medium enters the working medium reservoir through a connecting pipeline, condenses, and releases heat. The reproducing process is carried out under a vapor pressure lower than that of the working process. Thus the heat pump temperature rises in the reproducing process is smaller than the heat pump temperature rises in the working process according to the relationship between the saturated vapor pressures of the working medium or the absorbing solution and the temperature as illustrated in FIG. 3. Thus, the compression heat pump can concentrate the absorbing solution at a smaller temperature rise, and hence achieving a higher Coefficient of Performance (COP).

According to one embodiment of the present invention, the heat pump cycle system in the present invention has a simple structure, and is more cost effective to manufacture. In addition, the reproducing process of the present invention has a high Coefficient of Performance (COP), and can be carried out at a time when the general electricity consumption is slow, thereby achieving a high efficiency on energy consumption and cost. In the method of providing combined cooling and heating supply of present invention, an efficient heating supply and/or cooling supply can be achieved, with the reproducing process, during an electricity consumption trough, as well as, with the working process during an electricity consumption peak. Thus the peak load shifting is achieved by effectively utilizing the low ebb electricity. Therefore, the present invention can provide a system and a method for high-efficiency energy storage.

The preferred embodiments, detailed description, and the accompanying drawings are set forth below solely for illustration purpose, in order for those skilled in the art to fully understand this invention and thereafter implement the solution according to the description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a flow chart of a heat pump cycle system according to the first preferred embodiment of the present invention.

FIG. 2 illustrates a flow chart of a heat pump cycle system according to the second preferred embodiment of the present invention.

FIG. 3 illustrates a graphical relationship between the saturated vapor pressure of the lithium bromide saturated solution and the temperature, as well as a graphical relationship between the water saturated vapor pressures and the temperature.

DETAILED DESCRIPTION

Various embodiments of the present invention are now described with reference to the accompanying drawings. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the current invention and their specific embodiments, structures, features and functions. It is understood that these specific details by no means limit the scope of the present invention.

FIG. 1 illustrates a flow chart of a heat pump cycle system according to the first embodiment of the present invention. As referenced in FIG. 1, the heat pump cycle system, in one preferred embodiment, comprises a working medium reservoir 40, an absorbing solution reservoir 10, and a compression heat pump. The compression heat pump utilizes technologies well known to those skilled in the art. In another preferred embodiment, the compression heat pump comprises a compressor 30, a condenser 11, a throttle valve 20, and an evaporator 41 connected via pipelines. The circulation loop of the compression heat pump contains a refrigeration cooling medium, preferably, an R134a refrigeration cooling medium. The working medium reservoir 40 contains a working medium. The working medium reservoir 40 further comprises a first heat exchanger 42, and the evaporator 41. A cooling medium circulates in the first heat exchanger 42 of the working medium reservoir 40, and supplies heat energy to the working medium when the working medium evaporates. The cooling medium provides cooling to users upon the cooling medium releasing its heat energy, and drops its temperature. The absorbing solution reservoir 10 contains an absorbing solution. The absorbing solution reservoir 10 further comprises a second heat exchanger 12 and the condenser 11. The absorbing solution in the absorbing solution reservoir 10 concentrates as the working medium evaporates. When the absorbing solution absorbs the steam of the working medium, the absorbing solution is diluted, and releases the absorption heat. A heating medium circulates in the second heat exchanger 12, absorbs the absorption heat released as the absorbing solution absorbs the steam of the working medium. The heating medium provides heating to users upon absorbing the absorption heat and raises its temperature. The working medium reservoir 40 is connected with the upper portion of the absorbing solution reservoir 10 through a steam passage 50, which allows the working medium to flow between the working medium reservoir 40 and the absorbing solution reservoir 10. The working medium filled in the working medium reservoir 40 is one of or a mixture of water, ammonia, methanol and ethanol. The absorbing solution in the absorbing solution reservoir 10 comprises above disclosed working medium and an absorbent. The absorbent is one or a mixture of LiBr, NaBr, KBr, NH₄Br, MgBr₂, CaBr₂, LiI, NaI, KI, NH₄I, MgI₂, CaI₂, LiCl, NaCl, KCl, NH₄Cl, MgCl₂, CaCl₂, LiNO₃, NaNO₃, KNO₃, NH₄NO₃, Mg(NO₃)₂ and Ca(NO₃)₂. Those skilled in the art can choose a suitable working medium and absorbent in accordance with the operating condition.

Because the higher the concentration of the absorbing solution, the greater the absorption capacity is, the absorbing solution in the absorbing solution reservoir 10 is preferably, a saturated solution, or alternatively a supersaturated solution with the crystal of the absorbent in the absorbing solution reservoir 10 even after the working process.

FIG. 2 illustrates a flow chart of the heat pump cycle system according to the second embodiment of the present invention. As shown in FIG. 2, the heat pump cycle system, in another embodiment, comprises absorbing solution circulation pump 61 with a sparger 62 and a working medium circulation pump 71 with a sparger 72. The absorbing solution circulation pump 61 dispenses the absorbing solution in the absorbing solution reservoir 10 to the sparger 62. The working medium circulation pump 71 dispenses the liquid working medium in the working medium reservoir 40 to the sparger 72. In one embodiment of the present invention, a compression heat pump condenser is installed in the connecting pipeline between the working medium circulation pump 71 and the sparger 72. In another embodiment of the present invention, the evaporator 41 of the compression heat pump can also be configured to situate inside the working medium reservoir 40, or alternatively in the circulation loop of the first heat exchanger 42. In another embodiment, the condenser 11 of the compression heat pump can be configured to situate inside the absorbing solution reservoir 10, or alternatively in the circulation loop of the second heat exchanger 12. Another embodiment of the present invention further comprises a heat source for the working medium. The heat source can be a solar thermal collector 81, a terrestrial heat device 82, a reclaimed-water supply device 83, and an air heat exchanger. According to one embodiment of the present invention, one or multiple heat sources can be utilized to supply heat energy to the working medium.

A third embodiment of the present invention is a method of providing combined cooling and heating supply that utilizes the heat pump cycle system illustrated in the second embodiment. The third embodiment comprises a working process and a reproducing process. In the working process, the heat pump cycle system supplies heating and cooling to the user. In the reproducing process, the heat pump cycle system concentrates the absorbing solution in order to supply highly concentrated absorbing solution and liquid working medium for the next working process.

One embodiment of the working process is described as the following. The working medium reservoir 40 and the absorbing solution reservoir 10 of the system are kept under a first pressure. The cooling medium circulates in the first heat exchanger 42, and the heating medium circulates in the second heat exchanger 12. Under the first pressure, the working medium in the working medium reservoir 40 absorbs the heat energy from the cooling medium in the first heat exchanger 42, and evaporates into the gaseous state. The cooling medium, with its temperature dropped as its heat energy absorbed by the working medium, is then supplies cooling to users. The gaseous working medium enters into the absorbing solution reservoir 10 through the gas passage 50, and is absorbed by the highly concentrated absorbing solution while releasing the absorption heat. The absorption heat is then absorbed by the heat medium in the second heat exchanger 12. As the temperature of the heating medium rises, and the heating medium supplies heating to the user. As the working medium in the working medium reservoir 40 continuously evaporates, and absorbed by the absorbing solution, the absorbing solution in the absorbing solution reservoir 10 dilutes. When the working medium in the working medium reservoir 40 completely evaporates, or when the concentration of the absorbing solution drops to a definite value, the working process stops.

According to one embodiment of the present invention, during the reproducing process, the gaseous working medium condenses and refills the working medium reservoir 40, the amount of working medium in the working medium reservoir 40 thus increases, and the concentration of the absorbing solution in the absorbing solution reservoir 10 also increases. According to one embodiment of the invention, during the reproducing process, the working medium in the absorbing solution in the absorbing solution reservoir 10 evaporates, and transfers back to the working medium reservoir 40. Specifically, the compressor starts the compression heat pump circulation with the technology well known by those skilled in the art. In the reproducing process, the working medium reservoir 40 and the absorbing solution reservoir 10 are kept under the second pressure. The evaporator 41 in the compression heat pump absorbs the heat energy of the working medium so that the temperature inside the working medium reservoir 40 drops. At the same time, the condenser 11 of the compression heat pump releases the heat energy to the absorbing solution so that the temperature inside the absorbing solution reservoir 10 rises. Thus the working medium in the absorbing solution in the absorbing solution reservoir 10 evaporates into the gaseous state. The gaseous working medium enters into the working medium reservoir 40 through the gas passage 50. The gaseous working medium then condenses under the low temperature inside the working medium reservoir 40. In a preferred embodiment, the low ebb electricity is utilized as the power for the compression heat pump during the electricity consumption trough. Under the second pressure, the concentration of the absorbing solution in the absorbing solution reservoir increases continuously. When the concentration reaches a certain point, the heat energy supplied by the condenser 11 is no longer enough for the working medium to evaporate from the absorption solution, the working medium is no longer being transferred back to the working medium reservoirs 40, and the reproducing process thereby stops. According to the embodiment of the invention, the working process and the reproducing process are carried out alternatively. Preferably, the working process is carried out during the electricity consumption peak, while the reproducing process is carried out during the electricity consumption trough. Thus the present invention will not only supplies cooling and heating efficiently, but also utilizes low ebb electricity.

In one embodiment of the present invention, lithium bromide is used as the absorbent, and water as the working medium. In another embodiment of the present invention, the second pressure is lower than the first pressure. In a preferred embodiment, the first pressure is higher than 1 kPa, and the second pressure is between 0.6 kPa and 1 kPa.

As shown in FIG. 3, the upper curve provides a graphical relationship between the saturated vapor pressure of the lithium bromide saturated solution and the temperature. The lower curve of this embodiment provides a graphical relationship between the saturated vapor pressure of water and the temperature. As shown in FIG. 3, during the reproducing process, with the second pressure around 0.6 kPa, the temperature inside the absorbing solution reservoir 10 kept higher than 51° C., and the temperature inside the working medium reservoir 40 around 0° C., the working medium in the absorbing solution in the absorbing solution reservoir 10 will continuously evaporate thereby generating gaseous working medium, and the gaseous working medium continuously condenses in the working medium reservoir 40. According to one embodiment of the invention, both the heating and cooling are provided by the compression heat pump.

Upon completion of the reproducing process, and during the working process, with the first pressure around 4.5 kPa, the working medium in the working medium reservoir 40 evaporates around 32° C. thereby cooling the surrounding. At the same time, the saturated absorbing solution in the absorbing solution reservoir 10 absorbs the working medium around 100° C. thereby releasing heat. And the temperature difference between the two reservoirs is kept around 68° C. Thus, under the first pressure, the working process occurs with the temperature rise from the working medium reservoir 40 to the absorbing solution reservoir 10 about 68° C.; and under the second pressure, the reproducing process occurs with the temperature rise about 51° C. Since the smaller the temperature rise, the lower the energy consumption of the compression heat pump, so long as a minimum temperature rise is met, according to the embodiment of the present invention, the compression heat pump will work at a relatively small temperature rise with improved energy efficiency. According to the embodiment of the present invention, those skilled in the art can choose appropriate pressure, from what has been illustrated in FIG. 3, for the working and reproducing processes according to the cooling and heating requirements.

While the foregoing disclosure discusses illustrative aspects and/or aspects, it should be noted that various changes and modifications could be made herein without departing from the scope of the described aspects and/or aspects as defined by the appended claims. Furthermore, although elements of the described aspects and/or aspects may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. Additionally, all or a portion of any aspect and/or aspect may be utilized with all or a portion of any other aspect and/or aspect. unless stated otherwise. 

1. A heat pump cycle system comprising a working medium reservoir, an absorbing solution reservoir, and a compression heat pump; wherein said working medium reservoir is connected with the upper portion of said absorbing solution reservoir through a steam passage; wherein said compression heat pump comprises a compressor, a condenser, a throttle valve, and an evaporator, all of which are connected through pipelines; wherein said working medium reservoir contains a working medium; wherein said working medium reservoir further comprises a first heat exchanger; wherein the evaporator of said compression heat pump is situated inside said working medium reservoir; wherein said absorbing solution reservoir is filled with an absorbing solution; wherein said absorbing solution reservoir further comprises a second heat exchanger; and wherein the condenser of said compression heat pump is situated inside the absorbing solution reservoir.
 2. The heat pump cycle system of claim 1 further comprising an absorbing solution recycle pump, an absorbing solution spray system, a working medium recycle pump, and a working medium spray system; wherein said absorbing solution recycle pump is situated between the absorbing solution reservoir and the absorbing solution spray system; wherein said absorbing solution recycle pump recycles the absorbing solution between the absorbing solution reservoir and the absorbing solution spray system; wherein said working medium recycle pump is situated between the working medium reservoir and the working medium spray system; wherein said working medium recycle pump recycles the working medium between the working medium reservoir and the working medium spray system; wherein said evaporator of the compression heat pump is situated inside the working medium reservoir, or in the working medium circulation loop, or in the circulation loop of the first heat exchanger; and wherein said condenser of the compression heat pump is situated in the absorbing solution reservoir, or in the absorbing solution circulation loop, or in the circulation loop of the second heat exchanger.
 3. The heat pump cycle system of claim 1, wherein said absorption solution comprises the working medium and an absorbent; wherein the working medium is selected from water, ammonia, methanol, ethanol, and mixtures thereof; and wherein the absorbent is selected from LiBr, NaBr, KBr, NH₄Br, MgBr₂, CaBr₂, LiI, NaI, KI, NH₄I, MgI₂, CaI₂, LiCl, NaCl, KCl, NH₄Cl, MgCl₂, CaCl₂, LiNO₃, NaNO₃, KNO₃, NH₄NO₃, Mg(NO₃)₂, Ca(NO₃)₂, and mixtures thereof.
 4. The heat pump cycle system of claim 1, wherein said absorbing solution is a saturated solution or a supersaturated solution.
 5. The heat pump cycle system of claim 1 further comprising at least one of a solar thermal collector, a terrestrial heat device, a reclaimed-water supply device, and an air heat exchanger, for supplying heat to the fires heat exchanger in the working medium reservoir.
 6. A method for providing combined cooling and heating supply utilizing the heat pump cycle system of claim 1 comprising: a working process; wherein under a first pressure, the cooling medium circulates in the first heat exchanger, the heating medium circulates in the second heat exchanger, and the working medium in the working medium storage pump absorbs the heat of the cooling medium and evaporates to form a gaseous working medium; wherein the gaseous working medium enters the absorbing solution reservoir, and is absorbed by the absorbing solution with heat being released; and wherein the cooling medium supplies cooling, and the heating medium supplies heating; and a reproducing process; wherein under a second pressure, the compression heat pump starts, the evaporator absorbs heat, the condenser releases heat with which the absorbing solution is heated and the working medium evaporates into the gaseous working medium from the absorbing solution, the gaseous working medium enters the working medium reservoir and condenses into a liquid; and wherein the working process and the reproducing process are carried out alternatively.
 7. The method of claim 6, wherein the second pressure is lower than the first pressure.
 8. The method of claim 6, wherein the compression heat pump utilizes electricity when the general electricity consumption is low.
 9. The method of claim 6, wherein the first pressure is higher than about 1 kPa, and the second pressure is between about 0.6 kPa and about 1 kPa. 